1. Field of the Invention
The present invention relates to a foaming or effervescing apparatus for driving out the residual air from containers, especially bottles, that are filled with liquid material that can foam or effervesce. The apparatus includes a nozzle mechanism that is disposed above a conveying section or means that feeds the not-yet-sealed containers, which are filled with the foamable material, in an upright state to a sealing device that is provided with a sealing station. At a spraying station that in the conveying direction of the conveying means is located prior to the sealing station, the nozzle mechanism introduces a stream of gaseous or liquid medium that induces foaming; this involves preferably a stream of water or a stream of the liquid material with which the containers are filled, introduced into the liquid material in those containers that move past below the nozzle mechanism for the purpose of foaming the liquid material in the containers and driving out the residual air in those containers via the thus-formed foam. The foaming apparatus also includes a control device for varying the distance of the spraying station from the sealing station as a function of the conveying speed of the conveying means.
2. Description of the Related Art
An apparatus of the aforementioned general type is known from German Pat. No. 33 11 200--Patzwahl dated Apr. 5, 1984, which corresponds to U.S. Pat. No. 4,514,953--Patzwahl dated May 7, 1985, and, when a foamable liquid material, especially beer, is dispensed into containers, is used, prior to sealing the containers, to drive out, via foaming of the liquid material, the residual air that is present in the bottles after the liquid is dispensed therein. This prevents impairment of the taste and life of the dispensed material.
With the heretofore known apparatus, to foam the liquid material, i.e. to drive out the residual air, each container that is filled with material and is disposed on the conveying means that feeds the containers to the sealing station of the sealing device, is conducted past below a single spray nozzle that forms the nozzle mechanism. From this single spray nozzle, a stream of a liquid that induces foaming is sprayed into the container, so that the material dispensed in the container is stimulated to form foam, whereby the residual quantity of air is driven out by this foam. For an optimum foaming, it is desirable that the material foam, i.e. the head formed by this foam, reach the upper mouth of the container when the pertaining container reaches the sealing station, where it is capped and sealed. Since it is undesirable not only to have too great of a foaming action, or any foaming at all, due to the losses of material that occur and the contamination of the sealing station, but also to have too little of a foaming action due to the insufficient driving-out of the residual air from the pertaining container, the time (foaming time) between the time the liquid that induces foaming is sprayed in and the sealing of the pertaining container must be optimally selected. This means that the distance of the spraying position at which the liquid that induces foaming is sprayed into the pertaining container from the sealing station must be set as a function of the conveying speed of the conveying means in conformity with the optimum foaming time, and in particular must be adjusted in such a way that the spray nozzle, i.e. the spraying position, must have a lesser distance from the sealing station at lower conveying speeds of the conveying means than at greater conveying speeds of the conveying means. In order to achieve this, with the heretofore known apparatus the spray nozzle is provided at the free end of a support arm that is pivotable about the axis of rotation of a transport star that forms the conveying means and that rotates synchronously with a filling machine that is connected ahead of it. Thus, by pivoting the support arm, the spray nozzle can be adjusted along the conveying means.
One drawback of this heretofore known configuration is that mechanically movable parts are required for adjusting the distance of the spraying position from the sealing station; these movable parts entail a relatively expensive and complicated construction that is particularly susceptible to failure. A further drawback is that when the capacity of the filling machine is reduced during operation, and hence when the conveying speed of the conveying means is reduced, the arm that carries the spray nozzle must be pivoted in the conveying direction of the conveying means, so that unavoidably one or more of the containers is supplied with the stream of the liquid that induces foaming for a longer period of time than is acceptable for a satisfactory operation of the foaming apparatus, thus resulting in an over foaming of the liquid material in the containers.